WASHINGTON — U.S. automakers have surpassed foreign brands for the first time in a survey that measures the quality of new cars and trucks.

J.D. Power and Associates said Thursday that owners of vehicles made by Detroit automakers reported fewer problems on average during the first 90 days of ownership than those built by companies based overseas.

It was the first time that has happened in the 24 years the industry research group has conducted the annual quality study that is a closely watched measure of the durability and reliability of vehicles.

U.S. automakers have long lagged foreign brands, especially those from Asian manufacturers like Toyota, which many consumers believe produce higher quality cars and trucks than General Motors, Ford and Chrysler.

But J.D. Power said Ford Motor Co. showed some of the biggest gains in quality among individual brands, moving into the fifth spot. Porsche was the top scorer. Toyota Motor Corp., which has suffered through huge safety recalls earlier this year, saw its score drop.

"Domestic automakers have made impressive strides in steadily improving vehicle quality," said David Sargent, J.D. Power's vice president of global research.

The study ranks vehicles according to the number of problems reported per 100 vehicles. The overall average for the industry was 109 problems per 100 vehicles. That industry average has fallen steadily over the past decade.

U.S. manufacturers scored an average of 108 problems, while foreign companies posted 109 problems. That is a marked difference than just 10 years ago, when import brands had far fewer initial problems than those made by U.S. companies.

Luxury brands topped the list, with Acura and Mercedes-Benz holding the second and third spots. Daimler, which makes the Mercedes-Benz, had the best performing plant, an assembly facility in East London, South Africa.

Land Rover had the highest overall number of average problems with 170.

Ford was the best scorer among non-luxury brands, with 93 problems per 100 vehicles. J.D. Power said that Ford has shown steady improvement over the last nine years.

The rankings are closely watched by automakers, which frequently use them in advertising campaigns. Ford vice president of quality Bennie Fowler said in a statement that the survey shows Ford's "steady and meticulous attention to new model launches."

Toyota's ranking dropped to the 21st spot, down from the sixth ranking in 2009. The Japanese automaker has built a strong reputation for vehicle quality, but has seen its image suffer after wide reports of unintended acceleration in Toyota vehicles. The company has recalled 9 million vehicles worldwide since October over problems with gas pedals and brakes in some models.

"Overall, we're disappointed but probably not surprised," said Jim Lentz, Toyota's top U.S. sales executive. "If you look at when the survey was fielded, it was right during the height of the recall and the intense coverage of the recall."

He said vehicles not involved in recall saw their scores go up in the study. He also noted that Toyota had six segment award winners, more than any other manufacturer.

"We are paying close attention to what the customer is telling us through J.D. Power."